formulation and evaluation of diclofenac transdermal gel · the transdermal drug delivery systems...
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Dr. Satyabrata Bhanja
Associate Professor
Department of Pharmaceutics, Malla Reddy College of Pharmacy, Maisammaguda, Dhulapally
Secunderabad-500014, India E-mail: [email protected]
Address for correspondence
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Formulation and Evaluation of Diclofenac Transdermal Gel
INTRODUCTION
The Transdermal drug delivery systems are self-
contained, discrete dosage forms which when applied
to intact skin deliver the drug through the skin at a
controlled rate to the systemic circulation[1].At
present, the most common form of delivery of drugs is
the oral route. While this has the notable advantages
of easy administration, it also has significant
drawbacks namely poor bioavailability due to hepatic
metabolism (first pass) and the tendency to produce
rapid blood level spikes leading to a need for high and
/or frequent dosing, which can be both cost
prohibitive and involvement[2].To overcome these
difficulties there is a need for the development of new
drug delivery system; which will improve the
therapeutic efficacy and safety of drugs by more
precise (i.e. site specific), spatial and temporal
placement within the body thereby reducing both size
and number of doses. One of the methods most often
utilized has been Transdermal delivery. This delivery
transport therapeutic substance through the skin for
systemic effect. The success of Transdermal delivery
depends on the ability of the drug to permeate the
skin in sufficient quantities to achieve its desired
therapeutic effects. The skin is very effective as a
selective penetration barrier. Percutaneous
absorption involves the passage of the drug molecule
from the skin surface into the stratum corneum under
the influence of a concentration gradient and its
subsequent diffusion through the stratum corneum
and underlying epidermis through the dermis and into
the blood circulation. The skin behaves as a passive
barrier to the penetrating molecule. The stratum
corneum provides the greatest resistance to
penetration and it is the rate-limiting step in
percutaneous absorption[3].
Gels are transparent to opaque semisolids containing
a high ratio of solvent to gelling agent merge or
entangle to form a three-dimensional colloidal
network structure. This network limits fluid flow by
entrapment and immobilization of the solvent
molecules. The network structure is also responsible
for a gel resistance to deformation and therefore, its
RRRResearchesearchesearchesearch ArticleArticleArticleArticle
The present investigation is concerned with formulation and evaluation of Transdermal gels of Diclofenac sodium, anti-inflammatory drug, to circumvent the first pass effect and to improve its bioavailability with reduction in dosing frequency and dose related side effects. Twelve formulations were developed with varying concentrations of polymers like Carbopol 934P, HPMCK4M and Sodium CMC. The gels were tested for clarity, Homogeneity, Spreadability, Extrudability, Viscosity, surface pH, drug Content uniformity, in-vitro drug diffusion study and ex-vivo
permeation study using rat abdominal skin. FTIR studies showed no evidence on interactions between drug, polymers and excipients. The best in-vitro drug release profile was achieved with the formulation F4 containing 1 gm of Diclofenac sodium exhibited 6 h sustained drug release i.e. 98.68 % with desired therapeutic concentration which contains the drug and Carbopol 934p in the ratio of 1:2. The surface pH, drug content and viscosity of the formulation F4 was found to be 6.27, 101.3% and 3,10,000cps respectively. The drug permeation from formulation F4 was slow and steady and 0.89gm of Diclofenac sodium could permeated through the rat abdominal skin membrane with a flux of 0.071 gm hr-1 cm-2. The in-vitro release kinetics studies reveal that all formulations fits well with zero order kinetics followed by non-Fickian diffusion mechanism. Key words: Transdermal gel, Viscosity, In-vitro drug release, In-vitro drug release kinetics study, Ex-vivo permeation study.
ABSTRACTABSTRACTABSTRACTABSTRACT Satyabrata Bhanja*, P.Kishore
Kumar 1 , Muvvala Sudhakar1,
Arun kumar Das 2
*1Department of Pharmaceutics,
Malla Reddy College of Pharmacy,
Maisammaguda Secunderabad.
Andhra Pradesh. 2Department of Pharmaceutics, Malla Reddy Pharmacy College,
Maisammaguda Secunderabad.
Andhra Pradesh.
J. Adv. Pharm. Edu. & Res.
248 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
visco-elastic properties. Gels tend to be smooth,
elegant, non greasy and produce cooling effect and
utilize better drug release as compared to other semi-
solid formulation[4-5]. Gels have better potential as a
vehicle to administered drug topically in comparison
to ointment, because they are non-sticky requires low
energy during the formulation are stable and have
aesthetic value [6].
Diclofenac sodium (2-{2-[(2,6 dichlorophenyl)
amino]phenyl}acetic acid is a selective COX-2 inhibitor
used in a variety of inflammatory, pain and fever
condition [7]. Diclofenac sodium is an effective as
classical Non-steroidal anti-inflammatory drug
(NSAID) for the relief of a wide variety of pain and
inflammatory conditions, but it is better tolerated
than other (NSAID’s). After oral administration the
drug is rapidly and extensively absorbed. It is rapidly
distributed, extensively bound to albumin and
eliminated with a terminal half-life of about 2hr.
Molecular Weight is 296.149, Protein binding More
than 99%,Metabolism by Hepatic Excretion of the
unchanged drug in urine and faeces is negligible.
Generally the formulations of Diclofenacsodium
commercially available are in oral and rectal form.
More recently, a topical gel formulation will be
introduced specifically for the treatment of localized
painful and inflammatory condition, such as soft tissue
musculoskeletal disorders and osteoarthritis. So the
present study, formulation and evaluation of
Diclofenac sodium transdermal gel will attempt to
increase the efficacy of the drug at the site of action.
MATERIALS AND METHODS
Materials:
Diclofenac sodium was a gift sample from Yacht
Pharma, Hyderabad. Carbopol 934P and Sodium CMC
were purchased from S.D. Fine chem. Ltd, Mumbai.
HPMCK4M was purchased from Yarrow chemicals ltd,
Mumbai. All other reagents used were of analytical
grade.
Preformulation studies:
Characterization of Diclofenac sodium:
Description
The sample of Diclofenac sodium was analysed for its
nature, colour and taste.
Melting Point
The melting point was determined by using thiesel’s
tube apparatus method.
Drug Excipient compatibility studies:
The drug polymer and polymer-polymer interaction
was studied by the FTIR spectrometer using Shimadzu
8400-S, Japan. Two percent (w/w) of the sample with
respect to a potassium bromide disc was mixed with
dry KBr. The mixture was grind into a fine powder
using an agate mortar and then compressed into a KBr
disc in a hydraulic press at a pressure of 1000psi. Each
KBr disc was scanned 16times at 2 mm/sec at a
resolution of 4 cm-1 using cosine apodization. The
characteristic peaks were recorded.
Preparation of Transdermal Gels
1% w/w Diclofenac sodium Transdermal gels were
prepared by using different Concentrations of
polymers such as Carbopol 934P, HPMCK4M and
Sodium CMC. The formulation data for the preparation
of Diclofenac sodium Transdermal gels using Carbopol
934P, HPMCK4M and Sodium CMC in different ratio’s
is shown in [Tables 01]
Procedure:
Accurately weighed amount of Polymers (Carbopol
934P, HPMC K4M and Sodium CMC) in four different
ratios was placed in known amount of distilled water
(Twelve different formulations were prepared using
varying concentrations of Carbopol 934P, HPMC K4M
and Sodium CMC). After complete dispersion, the
polymer solution was kept in dark for 24 hours for
complete swelling. Accurately weighed amount of
Diclofenac sodium was dissolved in a specified
quantity of suitable solvent. The drug solution was
added slowly to the aqueous dispersion of polymer
with the help of high speed stirrer (500 rpm) taking
precaution that air did not entrap. Finally, the
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
249 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
remaining ingredients were added to obtain a
homogeneous dispersion of gel.
Evaluation of Gels
About twelve formulations i.e. F1 to F12 were
conducted. Gels were evaluated for their clarity, pH,
viscosity, spreadability, extrudability, skin irritation
test, percentage drug content, in-vitro diffusion
studies, in-vitro drug release kinetic study, ex-vivo
permeation studies using rat abdominal skin and
stability studies by using standard procedure. All
studies were carried out in triplicate and average
values were reported.
Clarity
Clarity of various formulation was determined by
visual inspection under black and white background
and it was graded as follows: turbid +; clear ++; very
clear (glassy) +++. The results are shown in [Table
02].
Homogeneity:
All developed gels were tested for homogeneity by
visual inspection after the gels have been set in the
container. They were tested for their appearance and
presence of any aggregates. The results are shown in
[Table 02].
Consistency
The estimation of consistency of the prepared gels
was done by dropping a cone attached to a holding
rod from a fixed distance of 10cm in other way that it
should fall down on the centre of the glass cup was
filled with the gel. The penetration by the cone was
accurately measured from the surface of the gel to the
tip of the cone inside of the gel. The distance traveled
by cone in the period was noted down after 10sec. The
results are shown in [Table 02]
Spreadability:
It was determined by wooden block and glass slide
apparatus. For the determination of spreadability,
excess of sample was applied in between two glass
slides and then was compressed to uniform thickness.
The weight (50gm) was added to pan. The time
required to separate the two slides i.e., the time in
which upper glass slide moves over the lower plates
was taken as a measure of spreadability (S).
It is calculated by using the formula:
S = M . L / T
Where M = wt. tied to upper slide
L = length of glass slides
T = time taken to separate the slides
The results are shown in [Table 02].
Extrudability
Extrudability test was carried out by using Pfizer
hardness tester. 15gm of gel was filled in collapsible
aluminium tube. The plunger was adjusted to hold the
tube properly the pressure of 1kg/cm2 was applied for
30 sec. The quantity of the gel extruded was weighed.
The procedure was repeated at three equidistance
places of the tube. The test was carried out in triplates.
The results are shown in [Table 02].
Surface pH [8]
2.5 gm of gel was accurately weighed and dispersed in
25ml of distilled water. The pH of the dispersion was
determined by using digital pH meter. The results are
shown in [Table 03].
Viscosity[8]
Viscosity was determined by using brookfield
viscometer. Viscosity measurements were carried out
at room temperature (25- 27°C) using a Brookfield
viscometer (Model RVTDV II, Brookfield Engineering
Laboratories, Inc, Stoughton, MA). The results are
shown in [Table 03].
Drug content[8]
A specified quantity (100mg) of developed gel and
marketed gel were taken and dissolved in 100ml of
phosphate buffer of pH 6.8. The volumetric flask
containing gel solution was shaken for the period 2hr
on mechanical shaker in order to get absolute
solubility of drug. This solution was filtered and
estimated spectrophotometrically at 285.0nm using
phosphate buffer (pH 6.8) as blank. The results are
shown in [Table 03].
In vitro diffusion study[8]:
Phosphate buffer of pH 6.8 was used for in vitro
release as receptor medium. The pretreated dialysis
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
250 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
sac (Cellophane membrane) was used in franz
diffusion cell. The gel sample was applied on the
membrane and then fixed in between donor and
receptor compartment of quality diffusion cell. The
receptor compartment contained phosphate buffer
(100ml) of pH 6.8. The temperature of diffusion
medium was thermostatically controlled at 37º ±
0.5ºC by surrounding water in jacket and the medium
was continuously stirred by magnetic stirrer at speed
of 600rpm. The sample at predetermined intervals
were withdrawn and replaced by equal volume of
freshly prepared fluid. The samples withdrawn were
spectrophotometrically measured at 285nm against
their blank. The results are shown in [Fig. 07 -10].
Drug release kinetic studies
Various models were tested for explaining the kinetics
of drug release. To analyze the mechanism of the drug
release rate kinetics of the dosage form, the obtained
data was fitted into zero-order, first order, Higuchi
and Korsmeyer-Peppas release model, to study the
drug release from the dosage form. The results are
shown in [Table 04].
Zero order release rate kinetics:-
To study the zero-order release kinetics the release
rate data are fitted to the following equation.
F=K0t
Where ‘F’ is the drug release, ‘K’ is the release rate
constant and ‘t’ is the release time. The plot of % drug
release versus time is linear.
First-order release rate kinetics:-
The release rate data are fitted to the following
equation.
Log (100-F) = kt
A plot of log % drug release versus time is linear.
Higuchi release model:-
To study the Higuchi release kinetics, the release data
were fitted to the following equation.
F = kt1/2
Where ‘k’ is the Higuchi constant.
In Higuchi model, a plot of % drug release versus
square root of time is linear.
Korsmeyer-Peppas release model:-
The release rate data were fitted to the following
equation.
Mt/M∞ = ktn
Where, Mt/M∞ is the fraction of drug released,
‘K’ is the release constant,
‘t’ is the release time.
‘n’ is diffusion exponent.
If n = 0.89, the release is zero order. If n = 0.45 the
release is best explained by Fickian diffusion, and if
0.45 < n < 0.89 then the release is through anomalous
diffusion or non fickian diffusion (Swellable &
Cylindrical Matrix). In this model, a plot of log
(Mt/M∞) versus log (time) is linear.
The drug release data of optimised tablet were fitted
to Zero-order, First-order, Higuchi and Korsmeyer-
Peppas model to study the kinetics of drug release.
Ex vivo permeation studies[9]
Tissue Isolation
Rats weighing 135-160 gm were used to obtain
freshly excised full thickness skin. Animal was
sacrificed by spinal dislocation. Hairs from abdominal
regions was removed by means of surgical and razor
taking care not to damage the epidermal surface,
Subcutaneous fats was removed carefully without
damaging to the skin.
In vitro drug permeation through rat abdominal
skin membrane
In vitro permeation of Diclofenac sodium transdermal
gel was studied through the rat abdominal skin
membrane. The skin membrane was mounted
between the donor and receptor compartment of the
standard Franz diffusion cell with a diffusion area of
2.1 cm2 and the acceptor compartment volume of
21ml.The two chambers were tied with the help of
springs so that the skin membrane did not move from
its place. The phosphate buffer pH 6.8 in the acceptor
compartment was continuously stirred at 600rpm
using a magnetic stirrer. The entire setup was placed
over a magnetic stirrer and the temperature was
maintained at 37˚±0.5°C by placing the diffusion cell in
a water bath. The selected gel (F4) containing 1mg of
Diclofenac sodium was placed into the donor
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
251 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
compartment. The amount of drug permeated through
the membrane was determined by removing aliquots
from the receptor compartment and by replacing the
same volume of buffer. The amount of Diclofenac
sodium in the diffusion samples was estimated by the
HPLC method.
The flux (J) through the membrane was calculated by
using the equation.
J = dQ / A dt
Where J is flux (mg h-1cm-2);
dQ/dt is the slope obtained from the steady-state
portion of the curve and
A is the area of diffusion (cm2)
HPLC analysis:
Instrument: youngling instrument
Software: Autochro 3000+
Column: C18, 5µm
Lambda max: 285nm
Temp: 35˚C
Injection volume: 20µl
Time -10min
Mobile phase: Methanol: Phosphate buffer (4:1
ratio)
pH: adjusted to 2 with HCl
The results are shown in [Table 05] and [Fig 11]
Skin Irritation Test
The hair on the dorsal side of Wister albino rats was
removed by clipping 1 day before the experiment. The
rabbits were divided into 3 groups. Group 1 served as
control; group 2 received optimized formulation;
group 3 received 0.8% v/v aqueous solution of
formalin as a standard irritant. Finally, the application
sites were graded according to visual scoring scale.
Stability studies
The optimized formulation F4 was subjected to a
stability testing for the period of three months as per
ICH norms at a temperature of 25˚±2°C with relative
humidity RH= 60±5% and 40º ± 2°C with relative
humidity RH= 75±5%. The optimized formulation F4
was analyzed for the changes in appearance, pH,
percentage of drug content and in-vitro diffusion study
by procedure stated earlier. The results are shown in
[Table 06]
RESULTS AND DISCUSSIONS
The objective of the present study was to formulate
Transdermal gels of Diclofenac sodium. Total twelve
different Diclofenac sodium transdermal gels with
different polymer ratios were prepared. In order to
select the optimized formulation, various evaluation
parameters were checked and subjected to in-vitro
diffusion study and their release kinetic study were
observed. The optimized formulation was further
studied for ex-vivo permeation using rat abdominal
skin.
Preformulation studies
Characterization of Diclofenac sodium:
The following tests were performed according to
British Pharmacopoeia.
Description: A white or almost white powder
Solubility: Methanol and Ethanol
Melting Point: 296.149˚C
From these tests it was confirmed that the sample
complies with the monograph.
Compatibility studies
The incompatibility between the drug and excipients
were studied by FTIR spectroscopy. The results
indicate that there was no chemical incompatibility
between drug and excipients used in the formulation.
The results are shown in [Fig 01- 05].
Evaluation of Transdermal gels:
Clarity:
Carbopol 934P gels were found to be sparkling and
transparent, HPMC K4M gels were found to be
translucent. All gels were free from presence of
particles. The results are shown in [Table 02].
Homogeneity:
All developed gels (F1-F12) showed good
homogeneity with absence of lumps. The developed
preparations were much clear and transparent. The
results are shown in [Table 02].
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
252 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
Spreadability:
The value of spreadability indicates that the gel is
easily spreadable by small amount of shear. In
formulations F1 to F4, Spreadability of Carbopol 934P
gel was in the range 18.75- 27.39 g.cm/sec. In
formulations F5 to F8, Spreadability of HPMCK4M gel
was in the range 20.06- 24.27 g.cm/sec. In
formulations F9 to F12, Spreadability of Na CMC was
in the range of 19.07- 24.57 g.cm/sec, indicating
Spreadability of Carbopol 934P containing Diclofenac
sodium gel i.e. F4 was good i.e. 27.39 g. cm/sec as
compared to HPMC K4M gel and Na CMC gel. The
results are shown in [Table 02].
Extrudability:
The extrusion of the gel from the tube is an important
during its application and in patient acceptance. Gels
with high consistency may not extrude from tube
whereas, low viscous gels may flow quickly, and hence
suitable consistency is required in order to extrude
the gel from the tube. Extrudability of Carbopol 934P
gel i.e. F4 formulation was found to be Excellent when
compared to other formulations. The results are
shown below in [Table 02].
Surface pH:
The pH value of all developed formulations of
Carbopol gels (F1-F4) were in the range of 5.71- 6.27,
HPMC gels (F5-F8) were in the range of 6.45- 6.82 and
Na CMC gels (F9-F12) were in the range of 5.65- 6.91
which is well within the limits of skin pH i.e. 5.6-7.5.
Hence, it was concluded that all the formulations
could not produce any local irritation to the skin. The
results are shown in [Table 03].
Viscosity Measurement:
The Viscosity of the formulations i.e. F1-F4 containing
drug and Carbopol 934P were in the range of 1,92,000
-3,10,000 cps, whereas the formulations i.e F5-F8
containing drug and HPMC K4M were in the range of
1,36,000 – 1,47,000 cps, whereas formulations i.e F9-
F12 containing drug and Sodium CMC were in the
range of 1,52,000- 1,80,000 cps. From the results it
was found that the formulation F1 showed maximum
viscosity i.e. 3,20,000 cps and formulation F8 showed
minimum viscosity i.e. 1,36,000 cps.
The results are shown in[Table 03].
Drug Content:
The percentage drug content of all prepared gel
formulations i.e. F1 to F12 were found to be in the
range of 97.21±0.18 to 101.46±0.26%. The percentage
drug content of formulations was found to be within
the I.P limits. Hence methods adopted for gels
formulations were found suitable. The results are
shown in [Table 03].
In-vitro drug diffusion studies:
In-vitro drug release study of different gel
formulations i.e. F1 to F12 were carried out through
dialysis sac (cellophane membrane) and are plotted.
The percentage drug release for the formulations
containing drug and carbopol 934P i.e. F1 to F4 were
found to be in the range of 82.88% to 98.68% in 6
hours. Among these formulations, formulation F4
containing drug and carbopol 934P in the ratio1:2
showed high percentage of drug release i.e. 98.68% in
6 hours. The results indicate that increase in the
concentration of Carbopol 934p, increases the drug
release.
The percentage drug release for the formulations
containing drug and HPMC K4M i.e. F5-F8 were in the
range of 79.59 – 87.72% in 6 hours. Among these,
formulation F8 containing drug and HPMCK4M in the
ratio 1:4 showed highest percentage of drug release
i.e. 87.72% in 6 hours. From the above it was observed
that increase in the concentration of HPMC K4M,
increases the drug release.
The percentage drug release for the formulations
containing drug and Na CMC i.e. F9-F12 were found to
be in the range of 83.77 – 90.38% in 6 hours. Among
these, the formulation F10 containing drug and Na-
CMC in the ratio 1:1.5 showed highest percentage
drug release of drug release i.e. 90.38% in 6 hours.
From the above it was observed that increase in the
concentration of Na CMC increases the drug release.
The comparison of in-vitro drug release studies were
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
253 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
conducted for the formulations F4, F8 and F10. The
results are shown in [Fig 07-10].
From the above result it is observed that the
formulation F4 containing drug and Carbopol 934P in
the ratio 1:2 showed highest percentage drug release
i.e. 98.68% in 6 hours.
Drug release kinetics:
In-vitro drug release data of F1 to F12 were fitted to
zero order, first order, Higuchi and Korsmeyer-Peppas
equations to ascertain the pattern of drug release. The
results are shown in [Table 04]. In-vitro drug release
data for all the formulations F1 to F12 were subjected
to release kinetic study according to Zero order, First
order, Higuchi and Korsemeyer-Peppas equation to
ascertain the mechanism of drug release. Among the
zero-order and first-order, the R2 values were found
to be higher in zero-order. So, all the formulations
followed zero-order kinetics. But in case of
mechanism of drug release, between Higuchi and
Korsemeyer-Peppas equation, the R2 value were found
to be higher in Korsemeyer-Peppas equation and
release exponent “n” value less than 1 i.e. (n > 0.5).
This indicates that all the formulations followed non-
Fickian diffusion. Hence it was concluded that all the
formulations followed zero-order drug release with
non-Fickian diffusion.
Ex-vivo permeation studies:
It was concluded that the formulation F4 containing
drug, carbopol 934P in the ratio 1:2, showed good
spreadability, extrudability and invitro drug release.
On the basis of above results formulation F4 was
studied for ex-vivo permeation using rat abdominal
skin. The optimized formulation was analyzed by
HPLC method at 285nm for 6hrs release through rat
abdominal skin. The flux was calculated.
The results of drug permeation from optimized
formulation through the rat abdominal skin revealed
that Diclofenac sodium was released from the
optimized formulation and permeate through the rat
abdominal membrane and could possibly permeate
through the human abdominal membrane. The drug
permeation from F4 was slow and steady and 0.89gm
of Diclofenac sodium could permeate through the skin
membrane with a flux of 0.071 gm hr-1 cm-2. The
results are shown in [Table 05] and [Fig.11].
Skin irritation test:
Based on in-vitro diffusion study formulation F4
containing drug and Carbopol 934P in the ratio 1:2
was optimized. Furthur, Skin irritation test was
performed with optimized formulation F4 in white
rabbits divided in 3 groups. It was found that the gel
F4 causes no irritation or erythema.
Stability Studies:
Accelerated stability studies was conducted in best
formulation F4, according to ICH guidelines i.e.
25˚±2˚C/60±5%RH for first 30 days and
40˚±2˚C/75±5%RH upto 90 days. The results indicate
that there was no so much change in appearance, pH,
drug content and in-vitro drug release studies. The
results are shown in [Table 06].
Table 1: Formula for the preparation of Diclofenac sodium Transdermal gels using Carbopol 934P, HPMCK4M and
Sodium CMC
Ingredients F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12
Diclofenac sodium (gm) 1 1 1 1 1 1 1 1 1 1 1 1
Carbopol 934P (gm) 0.5 1 1.5 2 - - - - - - - -
HPMC K4M (gm) - - - - 2.5 3 3.5 4 - - - -
Sodium CMC - - - - - - - - 1 1.5 2 2.5
Triethanolamine (ml) 0.4 0.6 0.8 1.0 - - - - - - - -
Alcohol (ml) 20 20 20 20 - - - - - - - --
Propylene glycol (ml) 10 10 10 10 30 30 30 30 30 30 30 30
PEG 400 (ml) - - - - 7 7 7 7 7 7 7 7
Distilled water (ml) q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s
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254 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
Table 2: Clarity, Homogeneity, Spreadability, Extrudability Parameters
Formulation
Code Clarity Homogeneity Spreadability Extrudability
F1 + Satisfactory 18.75 +
F2 ++ Good 19.85 ++
F3 ++ Good 22.55 ++
F4 +++ Excellent 27.39 +++
F5 ++ Good 20.06 +
F6 ++ Good 21.08 ++
F7 ++ Good 23.54 ++
F8 ++ Good 24.27 + +
F9 ++ Good 19.07 ++
F10 +++ Excellent 21.81 +++
F11 ++ Good 24.57 ++
F12 ++ Good 23.25 ++
Table 3: pH, Viscosity and Drug Content (%)
Formulation code pH Viscosity (cps) Drug Content (%)
F1 5.71±0.05 3,20,000 98.53±0.21
F2 5.79±0.15 1,92,000 97.21±0.18
F3 6.12±0.02 2,40,000 98.92±0.27
F4 6.27±0.03 3,10,000 101.3±0.22
F5 6.64±0.02 1,44,000 101.46±0.26
F6 6.45±0.07 1,47,000 98.92±0.25
F7 6.82±0.05 1,38,000 98.82±0.31
F8 6.60±0.04 1,36,000 99.95±0.18
F9 6.91±0.02 1,52,000 97.94±0.33
F10 6.73±0.09 1,60,000 98.08±0.40
F11 5.98±0.12 1,70,000 97.24±0.38
F12 5.65±0.14 1,80,000 99.13±0.19
For all n=3±S.D.
Table 4: Drug release kinetics of all the formulations (F1 - F12)
Formulation code Zero order First order Korsmeyer-Peppas Higuchi
R2 R2 R2 N R2
F1 0.989 0.899 0.996 0.783 0.955
F2 0.990 0.871 0.997 0.780 0.955
F3 0.989 0.870 0.990 0.7765 0.951
F4 0.990 0.932 0.997 0.784 0.953
F5 0.990 0.922 0.993 0.788 0.951
F6 0.990 0.908 0.995 0.789 0.952
F7 0.984 0.969 0.944 0.784 0.927
F8 0.987 0.963 0.972 0.809 0.939
F9 0.989 0.927 0.983 0.787 0.942
F10 0.982 0.977 0.980 0.774 0.952
F11 0.987 0.967 0.972 0.789 0.940
F12 0.985 0.970 0.960 0.793 0.936
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
255 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
Table 5: Ex-vivo drug permeation of optimized Formulation F4
Time (h) Cumulative drug permeated (gm)
0 0
1 0.17
2 0.31
3 0.49
4 0.62
5 0.77
6 0.89
Table 6: Stability studies of formulation F4
Formulation Days
Temperature
and Relative
Humidity
Appearance pH Drug
content
In-vitro drug
release
F4 0 25˚±2˚C/60±5%RH Clear 6.27 101.3 98.68
F4 15 25˚±2˚C/60±5%RH Clear 6.25 101.1 98.60
F4 30 25˚±2˚C/60±5%RH Clear 6.20 99.8 98.50
F4 60 40˚±2˚C/75±5%RH Clear 6.18 99.5 98.35
F4 90 40˚±2˚C/75±5%RH Clear 6.15 99.2 98.20
Fig 1: FTIR Spectra of Diclofenac sodium
Fig 2: FTIR of Carbopol 934P
Fig 3: FTIR Spectra of HPMCK4M
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
256 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
Fig 4: FTIR Spectra of Sodium CMC
Fig 5: FTIR Spectra of Diclofenac sodium + Carbopol 934P + HPMCK4M + Sodium CMC
Fig 6: Surface pH of all the formulations (F1 to F12)
Fig 7: In-vitro drug release profile of formulations F1 to F4
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
257 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
Fig 8: In vitro drug release profile of formulations F5 to F8
Fig 9: In-vitro drug release profile of formulations F9 to F12
Fig 10: Comparison of In-vitro drug release profile of formulations F4, F8 and F10
Fig 11: Ex-vivo permeation of optimized formulation F4
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
258 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3
CONCLUSION
It was observed that Carbopol 934P gel containing
Diclofenac sodium in 1:2 ratio (F4) produced better
spreadability and consistency as compared to other
formulations. The developed F4 gel showed good
homogeneity, suitable pH, no skin irritation and good
stability. The maximum percentage of drug release
was found to be 98.68% in 6 hours in formulation F4.
The drug permeation from optimized formulation i.e.
F4 was slow and steady and 0.89 gm of Diclofenac
sodium could permeated through rat abdominal skin
membrane with a flux 0.071 gm hr-1 cm-2 and could
possibly permeate through human abdominal
membrane. The Carbopol 934P forms water washable
gel because of its water solubility and has wider
prospects to be used as a topical drug delivery system.
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How to cite this article: Satyabrata Bhanja*, P. Kishore
Kumar, Muvvala Sudhakar, Arun Kumar Das; Formulation and Evaluation of Diclofenac Transdermal Gel; J. Adv.
Pharm. Edu. & Res. 2013: 3(3): 248-259.
Source of Support: Nil, Conflict of Interest: Nil
Satyabrata Bhanja, et al.: Formulation and Evaluation of Diclofenac Transdermal Gel
259 Journal of Advanced Pharmacy Education & Research Jul-Sept 2013 Vol 3 Issue 3